This invention relates to the use of effect pigments including platy titanium dioxide pigments, titanium dioxide and/or iron oxide coated on inorganic platy substrates, and combinations of the same, in ingestible drugs including pharmaceuticals and related oral products. These pigments provides a unique optical effect in such ingested drugs. They can also be used in decorative applications for foods (e.g. in cake frostings, gelatin desserts and candy coatings) and drugs, as well as for functional uses, such as a unique way to mark/identify drugs. Such effects are not possible using conventional absorption colorants.
This invention relates to the use of effect pigments including pearlescent pigments and platy titanium dioxide pigments in ingestible and oral drug products. The resulting compositions are also a part of this invention.
As used in this specification, the term xe2x80x9cingestiblexe2x80x9d product means a product which is intended in the ordinary course of use to be swallowed, for instance, a foodstuff or beverage or an orally administered pharmaceutical composition. The type of ingestible product or oral composition is not restricted. The ingestible product or oral composition is preferably intended for human use. As used in this specification, the term xe2x80x9cdrugxe2x80x9d means a therapeutic agent, i.e., any substance, other than food, used in the prevention, diagnosis, alleviation, treatment or cure of disease in man and animals. The term thus encompasses, for example, both pharmaceuticals and vitamins and the like products.
Effect pigments per se are well known. These pigments are usually a laminar materials with relatively high indexes of refraction relative to the medium in which they are incorporated. As a result of the reflection and refraction of light, these pigments can exhibit pearl-like luster, and interference color and/or color travel. The effect pigments most often encountered commercially are those which are coating on a support, and particularly are titanium dioxide coated and iron oxide coated micas. One of the effect (pearlescent) pigments used in the present invention is the well-known titanium coated mica. The particle size of such pigments is preferably about 200 xcexcm or less and more preferably about 100 xcexcm or less.
Platy TiO2 pigments, i.e., titanium dioxide platelets which exhibit interference colors but are not deposited on a substrate, per se are known. These pigments have a laminar structure and are distinct from pearlescent pigments which, as just noted, are based on coating a support. By the term xe2x80x9cplatyxe2x80x9d is meant the pigment particles have an aspect ratio of at least about 2 to 1 and a largest dimension of about 1 to 150 xcexcm, and more preferably about 3 to 75 xcexcm. Therefore, a platy TiO2 interference pigment is defined as consisting of smooth platelets of TiO2 having a high aspect ratio and controlled thickness such that various interference colors are produced depending on the thickness of the platelet.
A number of other platy effect pigments are covered by this invention. They include, but are not restricted to, platy iron oxide pigments, platy bismuth oxychloride pigments, platy guanine pigments, platy aluminum oxide, platy silicon dioxide, platey pigments of the genreal formula MnxAlyFe2xe2x88x92(x+y)O3, platy metal flake pigments such as aluminum, and any combinations of these. The combinations may be blends of the various pigments, or depositions of one or more on another of these. For example, a platy iron oxide pigment may be used to create a unique optical effect in a coating. Alternately, iron oxide may be coated on a platy titanium dioxide substratum, achieving a distinctly different effect.
The effect pigments can be combined with natural colorants, color pigments or coloring fruit and plant extracts to give the food or pharmaceutical an interesting new shade. Examples of fruit and plant extracts that could be used as a colorant include carrot juice, red beet juice, elder juice, hibiscus juice, paprika extract and aronia extract. The effect pigment of the invention can add increased light and moisture protection to the colored food or pharmaceutical. Vitamin preparations, for example, can be stored for a longer period of time. Also in some cases, such as colored tablets, a delayed release of the active ingredients can be established or augmented.
The pigment is incorporated into the ingestible product or oral composition in any convenient manner. The pigment may be incorporated in a coating system, or alternately, in the composition itself. The amount is not restricted and any amount which provides the desired optical effect can be employed. In general, the total concentration of all coloring agents in the food or pharmaceutical should not exceed about 12% by weight, although it can go up to about 15% by weight. Some products can be colored with as low as about 0.005% by weight. Preferably, the amount of effect pigment is about 0.01 to 6% by weight, and more preferably, about 0.1 to 2% by weight. Where combined with another colorant, the mixture ratio of the effect pigment with the other colorant depends upon the desired effect and is preferably about 20:1 to 1:20 and more preferably about 5:1 to 1:1. A surprising and unexpected aspect of the present invention, and one unique to the platy TiO2 pigment is that very low concentrations can be employed while achieving the desired effect. An amount which is one-half or less of the amount of non-platy titanium dioxide-coated mica pigments can be used to achieve the same effect. Typically, a concentration of about 1 weight % or less can be employed.
Coatings on all types of food can be colored with the agent of the present invention. Examples include pigmented sugar in shellac coatings, both alcoholic and aqueous, coatings of oils and waxes in combination with gum arabic and with cellulose material such as hydroxypropylmethyl cellulose, cake decorations, compressed products, dragees, chewing gum, gum products, fondant products, marzipan, fillings, cocoa gum, glazes, chocolate containing products, ice cream, cereal, snacks, produce, cake bases, gel and gelatin products, candy, licorice, puddings, desserts, icings, beverages, milk products and the like. Colored tablets, gelatin capsules, coated tablets, ointments and syrups are other products of the present invention.
In order to illustrate the invention, various examples are set forth below. It will be appreciated, however, that these are intended to be illustrative and are not intended to be limiting.